Padlocks are commonly used to lock a hasp having a slot through which there is a projecting staple. The typical design of prior art padlocks includes a shackle or bow which fits through the loop of the staple and prevents the staple from removal through the hasp. The padlock case usually has within it a lock cylinder with a keyway or combination tumbler device with a latching mechanism to latch the end of the shackle and prevent its removal from the case.
The prior art padlocks have had features which allow the lock to be broken open, since the shackle can usually be sawed off or broken off to open the lock. Even if the shackle cannot be broken, it is possible to saw or break off the exposed staple.
Another problem with prior art padlocks involves the latching mechanism which holds the end of the shackle within the case. After a period of time, such latching mechanisms can become susceptible to jamming, preventing one from opening of the lock with a key.